McMaster University Autism iPS Research Study

Dr Karun Singh   

This is a Guest Post by our reader AJ

McMaster University Autism iPS Research Study

First, a very big thank you to Peter for kindly offering to allow me to write this guest post.

It is with great excitement that I am announcing the launch of what I believe is one of the most promising research projects in autism today – McMaster University’s Autism iPS Research Study.  In fact, I have been given the great privilege of helping McMaster University raise funds and awareness for this incredible endeavor. For those of you that aren’t familiar with McMaster University, it is Canada’s most research-intensive University, located in Hamilton, Ontario (just west of Toronto).

What is the McMaster University Autism iPS Research Study?

This research is being led by Dr. Karun Singh at McMaster University. You can learn more about Dr. Singh and his research at
 https://sccri.mcmaster.ca/people/karun-singh.  

The intent of this research is to study reprogrammed neurons from individuals with autism and gain key insights into the affected pathways that result in the various issues seen with ASD. Dr. Singh’s approach requires that the ASD child, and each parent, provide a blood sample and these blood samples are reprogrammed (for those of you familiar with iPS cells) into neurons. Dr. Singh studies the ASD child’s neurons, using the parental iPS neurons as controls.

To supplement the research, Dr. Singh also uses a tool called BioID. This tool uses biotinylation, or the process of attaching biotin to proteins and other macromolecules, to determine what the mutant version of an affected protein (assuming a causative mutation is known) is doing differently than the normal version of the same protein. 

Once Dr. Singh has conducted his research into an ASD individual’s neurons and completed his BioID analyses, the next step in the project is to run a variety of selected compounds to screen for compounds that will address the underlying cellular mechanisms that are causing the condition.  

In summary, Dr. Singh’s research at McMaster intends to:

i) Use BioID to elucidate what a mutant protein is doing differently than the normal protein (where a genetic mutation is known)
ii) Use iPS neurons via reprogramming to study ASD neurons (and the parental controls) to determine what is causing symptoms in that particular individual
iii) Once the above two are completed, select compounds for testing against the iPS neurons to see if any are able to address the underlying issue causing the condition

What Dr. Singh and McMaster need for this project to succeed

When I first spoke with Dr. Singh and understood what he intended to do, I was naturally very excited. This research can clearly make an enormous impact in moving the science ahead and helping our children get the treatment they need. But then I learned about the one thing that was preventing him from moving forward – funding. As some you may know, researchers often have challenges in obtaining funding for their research, even when working at great institutions and pursuing very worthwhile research.

Like many of you, as a proactive parent it struck me that this endeavor is so clearly worthwhile that I offered to both pursue funding for it and also raise awareness. Rather than waiting for government funding, I believed that affected families, individuals and organizations who understand the importance of this work would help fund it and allow it to move forward.

So, to each parent reading this, I’m asking for you to consider supporting this research in the following ways:

1. DONATE: McMaster University has a funding page for this specific endeavor at impacths.mcmaster.ca/autismips – kindly give as generously as you can as each dollar is spent specifically on this research. The great news is that McMaster is able to provide tax receipts for Canadian donors. If you are living outside Canada and are considering making a donation to McMaster University’s Autism iPS Research Fund, there may be more information you need. There are different giving options for international donors in the following countries: USA, United Kingdom, Hong Kong. If you reside in one of those countries, please do not give online, instead contact the fundraising team at impacths@mcmaster.ca to receive additional information.

If you’re outside of Canada, USA, United Kingdom, and Hong Kong, please donate online or by contacting impacths@mcmaster.ca

This project requires significant funding to move ahead, as the reprogramming of neurons alone can cost up to $12,000 CAD per individual. As the research requires that the child and both parents have their blood reprogrammed into neurons, we estimate that the total research costs could be roughly $50,000 CAD per genetic mutation studied in the lab.

If you are interested in supporting the research tied to a specific genetic mutation with research costs of $50,000 CAD, please contact Simone Moran directly (moransim@mcmaster.ca). Simone will make certain that your area of interest aligns with the academic priorities and help liaise with the research team if appropriate. 

2. ADVOCATE: Become an advocate for this project. This is a very important ask. Kindly let everyone you know, especially those affected by ASD, about this research at McMaster University so that either they can donate, advocate, or participate in this research. Further, if you would like to pursue getting charitable donations from the company you work for, organizations you are familiar with (such as an ASD group focused on a particular gene, etc.), or individuals with the financial flexibility to make such donations, please do so. You can also share updates about Dr. Singh’s work such as this article: https://brighterworld.mcmaster.ca/articles/mcmaster-helps-provide-new-insight-on-gene-mutations-associated-with-autism/
   
3. PARTICIPATE: In addition to the need for funding, Dr. Singh’s lab is in need of more participants for this research. The McMaster team is interested in obtaining the necessary blood samples from a significant number of individuals affected by ASD. If your family would consider being part of the research, please contact Dr. Singh’s team by contacting Dr. Elyse Rosa at rosae@mcmaster.ca to determine if you qualify. It is important to remember that the details of each child’s specific case will need to be assessed by the research team to determine if they are consistent with the aims of this research.

*Please note that there is no link between donations and participation in this research. Both matters are handled by separate teams, in a confidential manner.

This research project is just starting, and funding is essential to continue to move it forward. That is why it is so important that we raise as much money as possible to allow Dr. Singh to apply BioID and iPS reprogramming to as many ASD children as possible. Again, please donate as much as you can, encourage others to give, and get the message out about this incredible opportunity.

From personal experience, I can tell the community that as impressive as Dr. Singh’s qualifications are, and as impressive as the resources at McMaster University are, that what has impressed me the most is Dr. Singh’s dedication to helping families with ASD. He truly wants to better understand the causes of this condition at a cellular level. As Dr. Singh’s team makes discoveries in this endeavor, they will be sharing their findings with researchers around the world for the benefit of all.

If we (with the help of each and every single one of you) can get Dr. Singh’s ambitious research fully funded, then the positive impact on ASD families will be enormous. I really believe in Dr. Singh and I know that with adequate funding, he will get us much closer to finding better treatments for our kids.

I hope everyone is as excited as I am about this endeavor and that each person who reads this post will do everything you can do help raise awareness and funds to make this project a big success. This is the right project, at the right time, with the right research team – please join me in doing everything you can to help Dr. Singh succeed!

Take Away Points from Thinking Autism 2019 Conference in London

This is not a summary of the recent conference I attended in London, it is just the impressions I left with, which will be very different to those of the delegates and the other speakers.

Hopefully I do not upset too many people.

Here is information on the conference and PDF versions of the two presentations I gave.

This is the only autism event I have ever attended, other than a discussion over lunch at a university reunion where someone organised a meeting for those from our year with an interest in autism. Other than that, I have really only ever met a handful of autism parents face to face.

I did meet our reader Petra in Thessaloniki a few years ago.  As expected, Petra is a very nice person in reality and not just in the comments on this blog

This weekend I met face to face with Agnieszka, Natasa who comments frequently and helps run the Think Autism charity in the UK, as well as many others who comment less frequently. I met my first MAPS-type doctor, Richard Frye and had a chat over lunch. It was a bit one-sided because I know a lot about him and his research and he knows nothing about me and my online collection of research.

I did meet some of the UK doctors who have a child with autism and an interest in doing something about it.  I genuinely wish them all the best in reforming the system.

Yes, I do actually exist

One teacher from North London said that she had been wondering if I really exist. Now she knows I do.

Why does everyone seem to know you?

There is a magazine for autism parents in the UK and the lady who runs it came up to me to give me her card and asked why she had never heard of me, but so many others had.  The world has changed and blogs have advantages over print media - people like the comments and the hyperlinks.

Yes, an Alternative Reality for Autism

I was told a few years ago that I appear to live in a different world to most other people, at least when it comes to autism.  I suppose that is true and I do only very rarely encounter that other world.  This conference was one of those rare events.

In my world anything is possible, until proven otherwise. I prefer to keep it that way.

Many people do have a choice and over the decades you will get to see the consequences of those choices; for better or worse.

Since not all parents are science wizards, there should be some support from both public health and educational services to ensure every child has a basic level of provision.  That basic level is not very high anywhere in the world.

If you want more you have to go and find it.

How much effort do you really want to make? What short term discomfort are you willing to take to ensure a brighter future?

I am surprised how much variation there is.  Some parents will do just about anything, while some others do nothing.

Personally, I am a proactive person. When something is broken, I try to fix it. If the “expert” gives me lame excuses, I do not accept them; I look for different solutions and maybe a different “expert”. 

Clearly, I am far from typical.  Thank god.

I do not lie in bed at night wondering what will happen to my son when I am dead.  I do not get depressed about the curtailed life expectancy in severe autism; rather I think it is up to me to make a difference while I am still very much alive.  The future is very much determined by past actions.

Other people are very welcome to visit this alternative reality where an open-minded science-based approach is encouraged.  An open mind is actually more important than a clever mind.

I did mention to Dr Frye about Potassium Bromide (KBr) for autism/epilepsy and his first reaction was “child protective services!”, someone else once mentioned “that is for pets!”.  Actually, Potassium Bromide (KBr) was the original human drug for epilepsy and to this day is successfully used in Germany for treatment resistant pediatric epilepsy. It saves lives.  Untreated epilepsy will kill you. About 30% of epilepsy does not respond well enough to mainstream therapies. Numerous modern studies regarding KBr have been published.  You just have to keep an open mind.  The Germans, Japanese, Chinese may know something Americans do not.

I did get indirect feedback that an autism parent showed the German/Austrian KBr research to a leading US neurologist, I think it was Dr Chez, and his comment was that he wished he could prescribe it to patients. For the moment in the US it is dogs with epilepsy rather than children with Dravet’s Syndrome and others that benefit.

Italy has some nice doctors

I have noted before on my blog that within Europe, Italy seems very different. We had a presentation from a Gastroenterologist from Turin who has been studying the bowels of kids with autism for 15 years and regarded it as a perfectly normal thing to do. No UK Gastroenterologist would do this. We had a chat about Milan, which I am now becoming more familiar with due to my elder son studying there. The top Italian researcher Dr Fasano, whose research I have covered in this blog, has moved to the US.  (one less clever doctor in Italy).

Israel has some nice doctors

We took Monty to Israel earlier this year, but it was to see the historical sites rather than to see the doctors.  There were a couple of speakers from Israel talking about cannabis in autism. They were really interesting and “well-adjusted”, they know their area of research is a bit controversial, but they find a way forward. I did cover in a recent post that you can use PEA instead of cannabis and they are aware of this, but cannabis is their research drug. They say that PEA has fewer side effects.

In their medical practise they actively treat autism, which no medical doctor does in the UK.  

Poland has some nice doctors

We already knew that Agnieszka is busy helping people in Gdansk and much further afield.  She is busy helping the UK charity Thinking Autism.   A husband and wife research team came from Lublin to talk about the ketogenic diet with a very thorough science-based presentation. They suggest a PET scan might identify responders. I think this is actually just one very specific sub-type, because it relates “simply” to altered glucose uptake to the brain being the underlying biological problem.

America has the most Autism Doctors, by far, at least one of whom is also a nice guy

There are so many horror stories of American DAN-type doctors charging huge fees for consultations and testing, you might imagine them all to be evil. I have never consulted a DAN/MAPS doctor, but Dr Frye definitely is a good guy and very willing to share his knowledge with others.

I did actually put him on my Dean’s list a while back, with some encouragement from our reader Roger.

The United Kingdom has no “Autism Doctors”

Many of the parents I met were English and very many of them had all been seeing the same doctor, who was then banned from seeing patients with autism. In the United Kingdom autism is untreatable.

If you want treatment, call it something else like auto-immune encephalopathy.

I am so glad I do not live in the UK

Many parents in the UK really struggle to achieve anything meaningful in regard to treating autism. I am glad to live in a different reality where the main limiting factor is the science itself, not the absurd things the UK parents have to deal with.

Bumetanide Clinical Trial Success

We had the absurd situation recently when it seemed that in the second largest country in the EU, almost no hospitals wanted to participate in the Bumetanide Phase 3 European trial for autism.

Fortunately, one of the parents at the conference is a Psychiatrist working in London. He has an interest in autism, because his child has it and he is already involved in the Balvotam trial for autism. Hopefully his hospital will become another centre for the trial starting this summer, that would be a big success.

Come on Agnieszka, see more Patients

Lots of people ask me for my email address and you may have noticed I always encourage them to contact me in public on this blog. I do this for several reasons including.

I am not a doctor and I am not giving medical advice. The comments are just a public discussion tagged on to a blog written by a parent whose albeit lengthy scientific education was not in biology.

Some comments and the ensuing discussion are really interesting for other people and it would be a shame for it to be hidden away.

I do think people in Europe should be able to access safe, evidence-based, off-label therapies, of the kind that Dr Frye is openly prescribing at the Phoenix Children’s Hospital. This is not really permitted in the United Kingdom, although there is a tiny bit of “wriggle room” if you have money, perseverance and some knowledge yourself.

I did ask Agnieszka if she is going to get into the same kind of trouble in Poland that any doctor would in the UK, if she openly held an autism clinic. Apparently not. Is her husband going to like it? I suppose we will find out.

How many people would actually come to Poland for a one-stop diagnostic work-up, where you could choose from a menu of MRI, whole exome screening, sleep EEG, 24 hour EEG, full blood work up testing all the things Dr Frye would test in Phoenix, once you could actually get an appointment to see him. As our reader Roger has told us, it is not so easy to get an appointment to see Dr Frye.  I suggested having Dr Frye also review the data and that if it was clear that there were GI problems there could be a referral to our new friend in Turin who has been treating the guts of kids with ASD for 15 years. You could then proceed to actually trial the off-label drugs that were indicated. 

None of this is cheap, but it is much cheaper than doing the diagnostics in the US, or the UK if you could actually access it.

Then I was thinking why leave it at evidence-based therapies for autism. Why not treat other poorly managed neurological diseases like Multiple Sclerosis (MS), there are so many things that can be done and actually much cheaper than in the US.

Then I came down to earth and realized that actually very few parents, at least ones from the UK, would take out their wallet and pay for all these tests, even though it would be a fraction of the cost that they would pay in US.

In the United Kingdom people expect their healthcare to be free from cradle to the grave. If it is free, although you do pay via your taxes, you are not the customer. The patient is the consumer, but he/she has little say in the therapy. If you need eye glasses, you might spend a day trying on frames in different shops to see what suits you, but if you need an operation you will have little say in the type of operation, you will get what the guidelines says is the cost effective therapy. If you have prostate cancer, you will not get proton beam therapy, that was developed years ago to minimize the side effects by focusing the radiation onto only the affected tissue rather than zapping all the surrounding tissue and giving you possible severe side effects.    

Who would invest a few thousand pounds/dollars to diagnose their child’s autism as accurately as possible? And then start treatment.

It would be nice to think there would be a long line. I think there would initially be a line for prescriptions for bumetanide. The real idea though is to make a thorough investigation to rule out treatable ID, single gene autisms, metabolic dysfunctions etc, not to be a prescription signing service.

So, as I said to Agnieszka, don’t plan to give up your day job any time soon.  Have treating autism as a side-line, make a list of therapies that you think are evidence based. It would not include things like the Nemechek protocol, I think it would include things like Bumetanide, Dr Frye’s Leucovorin, Propranolol and the many existing drugs already tested in clinical trials.  For Nemechek you can buy his book, no doctor is needed.

Where are all the younger parents?

Given that I have one son already moved out of the country to go to University, I was expecting to be feeling old surrounded by all those young parents working out what to do with their very young children recently diagnosed with autism.  There were some parents in their 30s, but most were much older.

It was nice that at least one Grandpa was there, looking for ideas for his adult Grandson. I did actually make a point of pointing him towards the science relating to his issues.

The Microbiome comes from the Mother

This may be obvious, should not be forgotten and sounds quite catchy.

It does not matter so much what is in Dad’s microbiome. It does matter what is in his epigenome and of course his regular genes matter.

Mum/Mom provides here half of the child’s regular DNA, her epigenome, all of the mitochondrial DNA and all of the microbiome that filters through to the child during pregnancy and during delivery (assuming there was no C-section).

Conclusion  

Having spent a couple of days mainly with British parents dealing with autism, I came home and told everyone how glad I am that I do not live there.  It would drive me crazy!

They can wait for years to get a diagnosis

No doctor is supposed to treat autism, even comorbidities may go untreated, because that might imply you are treating autism.   But many people still think they have a world class healthcare system (in some areas this really is true).

US style free early intervention for very young children does not exist. 

They have a very backward-looking Autism Charity (NAS) that is dominant and supposedly represents them.

Provision of special schools is highly variable and often parents take legal action to get better provision.  This means the less able parents that do not know how to play the system have even less resources allocated to their kids. 

They have about 2,000 young people with autism locked up for years in small, poorly supervised, private mental institutions. Just today another horror story has been released about the abuse that can occur.

Whorlton Hall hospital abuse and how it was uncovered

The end result is some pretty browbeaten parents.

I was once asked if I would speak in the US and I asked what they would like me to speak about, it was very much TREAT AUTISM NOW !!!  Those are my kind of people.  More dynamic, pushier and demanding more – it is the only way to be.

The Israeli clinicians at the conference told us the only way they managed to move therapies, including cannabis, forward and actually treat autism was pressure on the government from parents. I guess Israelis know how to push. Now UK parents fly to Tel Aviv to treat their child with autism, some others fly to California and I met one nice lady who takes her daughter to Italy.

Making best use of existing NKCC1/2 Blockers in Autism

Azosemide C12H11ClN6O2S2  

Source: https://pubchem.ncbi.nlm.nih.gov/compound/azosemide

Today’s post may be of interest to those already using bumetanide for autism and for those considering doing so.  It does go into the details, because they really do matter and does assume some prior knowledge from earlier posts.

There has been a very thorough new paper published by a group at Johns Hopkins:-

Off-Label Use of Bumetanide for Brain Disorders: An Overview

It does cover all the usual issues and raises some points that have not been covered yet in this blog.  One point is treating autism prenatally. This issue was studied twice in rats, and the recent study was sent to me by Dr Ben Ari.  Short term treatment during pregnancy produced a permanent benefit.

Maternal bumetanide treatment prevents the overgrowth in the VPA condition

            

Brief maternal administration of bumetanide before birth restores low neuronal intracellular chloride concentration ([Cl⁻]_i) levels, produces an excitatory-to-inhibitory shift in the action of γ-aminobutyric acid (GABA), and attenuates the severity of electrical and behavioral features of ASD (9, 10), suggesting that [Cl⁻]_i levels during birth might play an important role in the pathogenesis of ASD (7). Here, the same bumetanide treatment significantly reduced the hippocampal and neocortical volumes of P0 VPA pups, abolishing the volume increase observed during birth in the VPA condition [hippocampus: P0 VPA versus P0 VPA + BUM (P = 0.0116); neocortex: P0 VPA versus P0 VPA + BUM (P = 0.0242); KWD] (Fig. 3B). Maternal bumetanide treatment also shifted the distribution of cerebral volumes from lognormal back to normal in the population of VPA brains, restoring smaller cerebral structure volumes (Fig. 3C). It also decreased the CA3 volume to CTL level after birth, suggesting that the increased growth observed in this region could be mediated by the excitatory actions of GABA (Fig. 3D). Therefore, maternal bumetanide administration prevents the enhanced growth observed in VPA animals during birth.

One issue with Bumetanide is that it affects both:-

·        NKCC2 in your kidneys, causing diuresis

·        NKCC1 in your brain and elsewhere, which is divided into two slightly different forms NKCC1a and NKCC1b

NKCC1 is also expressed in your inner ear where it is necessary for establishing the potassium-rich endolymph that bathes part of the cochlea, an organ necessary for hearing. 

If you block NKCC1 too much you will affect hearing.

Blocking NKCC1 in children and adults is seen as safe but the paper does query what the effect on hearing might be if given prenatally as the ear is developing.

Treating Down Syndrome Prenatally

While treating autism prenatally might seem a bit unlikely, treating Down Syndrome (DS) prenatally certainly is not.  Very often DS is accurately diagnosed before birth creating a valuable treatment window.  In most countries the vast majority of DS prenatal diagnoses lead to termination, but only a small percentage of pregnancies are tested for DS. In some countries such as Ireland a significant number of DS pregnancies are not terminated, these could be treated to reduce the deficits that will otherwise inevitably follow.

Timing of therapies for Down syndrome: the sooner, the better

The research does suggest that DS is another brain disorder that responds to bumetanide.

Back to autism and NKCC1

This should remind us that a defect in NKCC1 expression will not only cause elevated levels of chloride with in neurons, but will also affect the levels of sodium and potassium with neurons.

There are many ion channel dysfunctions (channelopathies) implicated in autism and elevated levels of sodium and potassium will affect numerous ion channels.  The paper does suggest that the benefit of bumetanide may go beyond modifying the effect of GABA, which is the beneficial mode of action put forward by Dr Ben Ari.

We have seen how hypokalemic sensory overload looks very similar to what often occurs in autism and that autistic sensory overload is reduced by taking an oral potassium supplement.

The paper also reminds us that loop diuretics like bumetanide and furosemide not only reduce inflow of chloride into neurons, but may also reduce the outflow. This is particularly known of furosemide, but also occurs with bumetanide at higher doses.

The chart below shows that the higher the concentration of bumetanide the strong its effect becomes on blocking NKCC1.

But at higher doses there will also be a counter effect of closing the NKCC2 transporter that allows chloride to leave neurons.

At some point a higher dose of bumetanide may have a detrimental effect on trying to lower chloride within neurons.

Since Dr Ben Ari’s objective is to lower chloride levels in neurons  it is important how freely these ions both enter and exit.  The net effect is what matters. (Loop diuretics block NKCC1 that lets chloride enter neurons but also block the KCC2 transporter via which they exit)

Is Bumetanide the optimal existing drug to lower chloride within neurons?  Everyone agrees that it is not, because only a tiny amount crosses into the brain. The paper gives details of the prodrugs like BUM5 that have been looked at previously in this blog; these are modified versions of bumetanide that can better slip across the blood brain barrier and then react in the brain to produce bumetanide itself.  It also highlights the recent research that suggests that Bumetanide may not be the most potent approved drug, it is quite conceivable that another old drug called Azosemide is superior.

The blood brain barrier is the problem, as is often the case.  Bumetanide has a low pH (it is acidic) which hinders its diffusion across the barrier.  Only about 1% passes through.

There is scepticism among researchers that enough bumetanide can cross into the brain to actually do any good.  This is reflected in the review paper.

The paper reminds us of the research showing how you can boost the level of bumetanide in the brain by adding Probenecid, an OAT3 inhibitor.  During World War 2 antibiotics were in short supply and so smaller doses were used, but their effect was boosted by adding Probenecid. By blocking OAT3, certain types of drug like penicillin and bumetanide are excreted at a slower rate and so the net level in blood increases.

The effect of adding Probenecid, or another less potent OAT3 inhibitors, is really no different to just increasing the dose of bumetanide.

The problem with increasing the dose of bumetanide is that via its effect on NKCC2 you cause even more diuresis, until eventually a plateau is reached.

Eventually, drugs selective for NKCC1a and/or NKCC1b will appear.

In the meantime, the prodrug BUM5 looks good. It crosses the BBB much better than bumetanide, but it still affects NKCC2 and so will cause diuresis.  But BUM5 should be better than Bumetanide + Probenecid, or a higher dose of Bumetanide.  BUM5 remains a custom-made research drug, never used in humans.

I must say that what again stands out to me is the old German drug, Azosemide.

In a study previously highlighted in this blog, we saw that Azosemide is 4 times more potent than Bumetanide at blocking NKCC1a and NKCC1b.

Azosemide is more potent than bumetanide and various other loop diuretics to inhibit the sodium-potassium-chloride-cotransporter human variants hNKCC1A and hNKCC1B

Azosemide is used in Japan, where recent research shows it is actually more effective than other diuretics

Azosemide, a Long-acting Loop Diuretic, is Superior to Furosemide in Prevention of Cardiovascular Death in Heart Failure Patients Without Beta-blockade 

As is often the case, Japanese medicine has taken a different course to Western medicine.

Years of safety information has already been accumulated on Azosemide.  It is not an untried research drug. It was brought to market in 1981 in Germany. It is available as Diart in Japan made by Sanwa Kagaku Kenkyusho and as a cheaper generic version by Choseido Pharmaceutical. In South Korea Azosemide is marketed as Uretin.

In any other sector other than medicine, somebody would have thought to check by now if Azosemide is better than Bumetanide.  It is not a matter of patents, Ben-Ari has patented all of the possible drugs, including Azosemide and of course Bumetanide.

So now we move on to Azosemide.

When researchers came to check the potency of the above drugs the results came as a surprise.  It turns out that the old German drug Azosemide is 4 times as potent as bumetanide.

The big question is how does it cross the blood brain barrier.

“The low brain concentrations of bumetanide obtained after systemic administration are thought to result from its high ionization (>99%) at physiological pH and its high plasma protein binding (>95%), which restrict brain entry by passive diffusion, as well as active efflux transport at the blood-brain barrier(BBB). The poor brain penetration of bumetanide is a likely explanation for its controversial efficacy in the treatment of brain diseases”

“… azosemide was more potent than any other diuretic, including bumetanide, to inhibit the two NKCC1 variants. The latter finding is particularly interesting because, in contrast to bumetanide, which is a relatively strong acid (pKa = 3.6), azosemide is not acidic (pKa = 7.38), which should favor its tissue distribution by passive diffusion. Lipophilicity (logP) of the two drugs is in the same range (2.38 for azosemide vs. 2.7 for bumetanide). Furthermore, azosemide has a longer duration of action than bumetanide, which results in superior clinical efficacy26 and may be an important advantage for treatment of brain diseases with abnormal cellular chloride homeostasis.”

Dosage equivalents of loop Diuretics

Bumetanide has very high oral bioavailablity, meaning almost all of what you swallow as a pill makes it into your bloodstream.

Furosemide and Azosemide have much lower bioavailability and so higher doses are needed to give the same effect.

Both Furosemide and Bumetanide are short acting, while Azosemide is long acting.

For a drug that needs to cross the blood brain barrier small differences might translate into profoundly different effects.

The limiting factor in all these drugs is their effect on NKCC2 that causes diuresis.

1mg of bumetanide is equivalent to 40mg of furosemide.

2mg of bumetanide is equivalent to 80mg of furosemide.

The standard dose for Azosemide in Japan, where people are smaller than in the West, is 30 mg or 60mg. 

Research suggests that the same concentration of Azosemide is 4x more potent than Bumetanide at blocking NKCC1 transporters, other factors that matter include:-

·        How much of the oral tablet ends up in the bloodstream.

·        How long does it stay in the blood stream

·        How much of the drug actually crosses the blood brain barrier

·        How does the drug bind to the NKCC1 transporters in neurons

·        How rapidly is the drug excreted from the brain

·        What effect is there on the KCC2 transporter that controls the exit of chloride ions from neurons.

All of this comes down to which is more effective in adults with autism 2mg of bumetanide or 60mg of Azosemide.

The side effects, which are mainly diuresis and loss of electrolytes will be similar, but Azosemide is a longer acting drug and so there will be differences. In fact Azosemide is claimed to be less troublesome than Bumetanide in lower potassium levels in your blood.

Conclusion  

The open question is whether generic Azosemide is “better” than generic Bumetanide for treating brain disorders in humans.

I did recently ask Dr Ben-Ari if he is aware of any data on this subject. There is none.

Many millions of dollars/euros are being spent getting Bumetanide approved for autism, so it would be a pity if Azosemide turns out to be better. (Dr Ben Ari’s company Neurochlore wants to develop a new molecule that will cross the blood brain barrier, block NKCC1 and not NKCC2 and so will not cause diuresis).

The hunch of the researchers from Hanover, Germany seems to be that the old German drug Azosemide will be better than Bumetanide.

I wonder if doctors at Johns Hopkins / Kennedy Krieger have started to prescribe bumetanide off-label to their patients with autism.  Their paper shows that they have a very comprehensive knowledge of the subject.

===========

I suggest readers consult the full version of the Johns Hopkins review paper on Bumetanide, it is peppered with links to all the relevant papers.

Off-Label Use of Bumetanide for Brain Disorders: An Overview

Bumetanide (BTN or BUM) is a FDA-approved potent loop diuretic (LD) that acts by antagonizing sodium-potassium-chloride (Na-K-Cl) cotransporters, NKCC1 (SLc12a2) and NKCC2. While NKCC1 is expressed both in the CNS and in systemic organs, NKCC2 is kidney-specific. The off-label use of BTN to modulate neuronal transmembrane Cl⁻gradients by blocking NKCC1 in the CNS has now been tested as an anti-seizure agent and as an intervention for neurological disorders in pre-clinical studies with varying results. BTN safety and efficacy for its off-label use has also been tested in several clinical trials for neonates, children, adolescents, and adults. It failed to meet efficacy criteria for hypoxic-ischemic encephalopathy (HIE) neonatal seizures. In contrast, positive outcomes in temporal lobe epilepsy (TLE), autism, and schizophrenia trials have been attributed to BTN in studies evaluating its off-label use. NKCC1 is an electroneutral neuronal Cl⁻importer and the dominance of NKCC1 function has been proposed as the common pathology for HIE seizures, TLE, autism, and schizophrenia. Therefore, the use of BTN to antagonize neuronal NKCC1 with the goal to lower internal Cl⁻ levels and promote GABAergic mediated hyperpolarization has been proposed. In this review, we summarize the data and results for pre-clinical and clinical studies that have tested off-label BTN interventions and report variable outcomes. We also compare the data underlying the developmental expression profile of NKCC1 and KCC2, highlight the limitations of BTN’s brain-availability and consider its actions on non-neuronal cells.

Btn Pro-Drugs and Analogs

To improve BTN accessibility to the brain, pro-drugs with lipophilic and uncharged esters, alcohol and amide analogs have been created. These pro-drugs convert to BTN after gaining access into the brain. There was a significantly higher concentration of ester prodrug, BUM5 (N,N – dimethylaminoethyl ester), in mouse brains compared to the parent BTN (10 mg/kg, IV of BTN and equimolar dose of 13 mg/kg, IV of BUM5) (Töllner et al., 2014). BUM5 stopped seizures in adult animal models where BTN failed to work (Töllner et al., 2014; Erker et al., 2016). BUM5 was also less diuretic and showed better brain access when compared to the other prodrugs, BUM1 (ester prodrug), BUM7 (alcohol prodrug) and BUM10 (amide prodrug). BUM5 was reported to be more effective than BTN in altering seizure thresholds in epileptic animals post-SE and post-kindling (Töllner et al., 2014). Furthermore, BUM5 (13 mg/kg, IV) was more efficacious than BTN (10 mg/kg, IV) in promoting the anti-seizure effects of PB, in a maximal electroshock seizure model (Erker et al., 2016). Compared to BUM5 which was an efficacious adjunct to PB in the above mentioned study, BTN was not efficacious when administered as an adjunct (Erker et al., 2016). In addition to seizure thresholds, further studies need to be conducted to assess effects of BUM5 on seizure burdens, ictal events, duration and latencies.

Recently, a benzylamine derivative, bumepamine, has been investigated in pre-clinical models. Since benzylamine derivatives lack the carboxylic group of BTN, it results in lower diuretic activity (Nielsen and Feit, 1978). This prompted Brandt et al. (2018) to explore the proposed lower diuretic activity, higher lipophilicity and lower ionization rate of bumepamine at physiological pH. Since it is known that rodents metabolize BTN quicker than humans, the study used higher doses of 10 mg/kg of bumepamine similar to their previous BTN studies (Olsen, 1977; Brandt et al., 2010; Töllner et al., 2014). Bumepamine, while only being nominally metabolized to BTN, was more effective than BTN to support anticonvulsant effects of PB in rodent models of epilepsy. This GABAergic response, however, was not due to antagonistic actions on NKCC1; suggesting bumepamine may have an off-target effect, which remains unknown. However, the anticonvulsive effects of bumepamine, in spite of its lack of action on NKCC1, are to be noted. Additionally, in another study by the same group, it was shown that azosemide was 4-times more potent an inhibitor of NKCC1 than BTN, opening additional avenues for better BBB penetration and NKCC1-antagonizing compounds for potential neurological drug discovery (Hampel et al., 2018).

Conclusion

The beneficial effects of BTN reported in cases of autism, schizophrenia and TLE, given its poor-brain bioavailability are intriguing. The mechanisms underlying the effects of BTN, as a neuromodulator for developmental and neuropsychiatric disorders could be multifactorial due to prominent NKCC1 function at neuronal and non-neuronal sites within the CNS. Investigation of the possible off-target and systemic effects of BTN may help further this understanding with the advent of a new generation of brain-accessible BTN analogs.